Does an increase in the 100-year flood estimate originate from climate or land-use change?
Climate variability (dry cycles to wet cycles) and land-use change play a significant role, but there is a large amount of uncertainty around the flood quantile estimates (the value of discharge corresponding to the 100-year flood), particularly if there isn’t a long record of observed data at a stream location.
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Related Content
Why do the values for the 100-year flood seem to change with every flood?
What is a 1,000-year flood?
How can a 1,000-year rainfall not result in a 1,000-year flood?
We had a "100-year flood" two years in a row. How can that be?
Where can I find flood maps?
How are floods predicted?
What are the two types of floods?
Guidelines for determining flood flow frequency—Bulletin 17C
Accurate estimates of flood frequency and magnitude are a key component of any effective nationwide flood risk management and flood damage abatement program. In addition to accuracy, methods for estimating flood risk must be uniformly and consistently applied because management of the Nation’s water and related land resources is a collaborative...
England, John F.; Cohn, Timothy A.; Faber, Beth A.; Stedinger, Jery R.; Thomas, Wilbert O.; Veilleux, Andrea G.; Kiang, Julie E.; Mason, Robert R.
Development of flood regressions and climate change scenarios to explore estimates of future peak flows
A new Web-based application, titled “Application of Flood Regressions and Climate Change Scenarios To Explore Estimates of Future Peak Flows”, has been developed by the U.S. Geological Survey, in cooperation with the New York State Department of Transportation, that allows a user to apply a set of regression equations to estimate the...
Burns, Douglas A.; Smith, Martyn J.; Freehafer, Douglas A.
Popular myths about flooding in Western Washington
Floods are the most destructive natural hazard in the Nation, causing more deaths and financial loss in the 20th century than any other natural disaster. The most significant 20 riverine floods of the 20th century for which data are available have killed more than 1,843 people and caused more than $50 billion (uninflated) in damages (Perry, 2000...
Jones, Joseph L.
Climate change, atmospheric rivers, and floods in California - a multimodel analysis of storm frequency and magnitude changes
Recent studies have documented the important role that "atmospheric rivers" (ARs) of concentrated near-surface water vapor above the Pacific Ocean play in the storms and floods in California, Oregon, and Washington. By delivering large masses of warm, moist air (sometimes directly from the Tropics), ARs establish conditions for the kinds of high...
Dettinger, M.
100-Year flood–it's all about chance
In the 1960's, the United States government decided to use the 1-percent annual exceedance probability (AEP) flood as the basis for the National Flood Insurance Program. The 1-percent AEP flood was thought to be a fair balance between protecting the public and overly stringent regulation. Because the 1-percent AEP flood has a 1 in 100 chance of...
Holmes, Robert R.; Dinicola, Karen
The world's largest floods, past and present: Their causes and magnitudes
Floods are among the most powerful forces on earth. Human societies worldwide have lived and died with floods from the very beginning, spawning a prominent role for floods within legends, religions, and history. Inspired by such accounts, geologists, hydrologists, and historians have studied the role of floods on humanity and its supporting...
O'Connor, Jim E.; Costa, John E.
Large floods in the United States: where they happen and why
The spatial distribution of large gaged floods throughout the United States shows that the locations of most of the largest flows are related to specific combinations of regional climatology, topography, and basin size. Key factors include the general northward trend of decreasing atmospheric moisture, proximity to oceanic moisture sources such as...
O'Connor, Jim E.; Costa, John E.
The "100-Year Flood"
Dinicola, Karen Floods and flood plains
Moreland, Joe A.
New US Geological Survey-led Research Helps California Coastal Managers Prioritize Planning and Mitigation Efforts Due to Rising Seas and Storms
New U.S. Geological Survey-led coastal modeling research presents state, federal, and commercial entities with varying storm and sea level-rise scenarios to assist with planning for future infrastructure and mitigation needs along the California coast.
USGS Science – Leading the Way for Preparedness
Learn About USGS Hazards Science and More About National Preparedness Month: The very nature of natural hazards means that they have the potential to impact a majority of Americans every year. USGS science provides part of the foundation for emergency preparedness whenever and wherever disaster strikes.
Study Links Major Floods in North America and Europe to Multi-Decade Ocean Patterns
The number of major floods in natural rivers across Europe and North America has not increased overall during the past 80 years, a recent study has concluded. Instead researchers found that the occurrence of major flooding in North America and Europe often varies with North Atlantic Ocean temperature patterns.
Stormy weather: How the USGS goes to work monitoring its effects
Atmospheric rivers are a global weather phenomenon that can bring large amounts of rain or snow to the U.S. West Coast each year. These rivers of wet air form over the Pacific Ocean near Hawaiʻi and pick up large amounts of moisture from the tropics and on their way to the West Coast. This moisture is carried in narrow bands across the Pacific Ocean to California, Oregon, Washington and Nevada.
Fragmented Patterns Seen in the Recent History of U.S. Floods
Some regional trends; no widespread national pattern
Measuring streamflow in fast moving floodwater.
USGS hydrographer measuring streamflow using a handheld Acoustic Doppler Velocimeter in fast moving floodwater Cajon Creek near Keenbrook, California.
Video - When rivers rise: warning you before the next flood (WCET)
The Anatomy of Floods: The Causes and Development of 2011's Epic Flood Events
Flooding costs the United States more than $7 billion per year and claims more than 90 lives annually. During the Spring and Summer of 2011, the central U.S. experienced epic flooding, while Hurricane Irene followed by Tropical Storm Lee caused severe flooding in the east and northeastern U.S, setting numerous flood records at USGS streamgages. Dr. Robert Holmes discusses
...
Flood Sign in Tualatin River, OR
Peak flood height of 1996 flood, as observed in the Tualatin River, OR.
Streamgages: The Silent Superhero
Whether you drink water from your tap, use electricity or canoe down your local river, chances are you benefit from USGS streamgage information. So what is a streamgage and what does it do for you? This CoreCast episode gives you the inside scoop on your silent superhero.
Transcript and captions available soon.
Interview: 2009 Fargo, ND Flooding
Interview with USGS crews regarding the 2009 flooding events in Fargo, ND.
Two 500-Year Floods Within 15 Years?
We talk to Bob Holmes about some of the recent flooding events occuring in the Midwest, how does a 500-year flood occur twice in 15 years, and what do the recent events have in store for folks downriver.
We had a "100-year flood" two years in a row. How can that be?
Listen to hear the answer.
Poster: 100-Year Flood--It's All About Chance
Flooding of the Sorlie Bridge
The Sorlie Bridge between Grand Forks, North Dakota and East Grand Forks, Minnesota, during the 1997 Red Riber of the North flood.
